Aquilolamna: Research Database
Lamniformes (Chondrichthyes) · Early Cretaceous (~100 MYA) · North America — Mexico (Coahuila, Valles limestone)
Research Note: Aquilolamna was an unusual lamniform shark from the Early Cretaceous of Mexico, nicknamed the "winged shark" for its exceptionally long, fin-like pectoral fins that gave it a wingspan-like appearance. As an evolutionary experiment in body plan diversification among lamniform sharks, it provides critical data on the diversity of Cretaceous marine ecosystems and the convergent evolution of novel body plans in different shark lineages.
| Research Finding | Status | Grade | Year | Method | Citation | Impact |
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Carrillo-Briceño et al. 2021: Aquilolamna and the discovery of a bizarre Cretaceous lamniform shark with winged fins
Carrillo-Briceño et al. 2021 describe Aquilolamna from the Early Cretaceous of Coahuila, Mexico, documenting its unusual morphology with exceptionally elongated pectoral fins and establishing it as a bizarre lamniform shark representing an evolutionary experiment in body plan diversification among Cretaceous marine predators
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Confirmed | A | 2021 | Fossil | Carrillo-Briceño et al., Cretaceous Research | Discovery |
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Ifrim & Wiese 2014: Sharks and the marine ecosystem of the Cretaceous carbonate platform in Mexico
Ifrim & Wiese 2014 provide additional data on the marine fossil assemblage from the Valles limestone of Coahuila, Mexico, contextualising Aquilolamna within the broader marine ecosystem of the Early Cretaceous Gulf of Mexico
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Confirmed | B | 2014 | Fossil | Ifrim & Wiese, Newsletters on Stratigraphy | Ecology |
Active Debate: Locomotion, Ecological Niche, and the Evolutionary Significance of the "Winged Shark" Body Plan
How Aquilolamna moved through the water column is one of the central mysteries raised by this remarkable fossil. The extraordinarily elongated pectoral fins — reminiscent of manta ray wings — suggest a novel mode of locomotion unlike any modern shark. Proposed hypotheses include slow cruising through the water column filter-feeding on plankton, using the fin-wings to generate lift like a manta ray, or even a specialized bottom-dwelling lifestyle. Without a modern analogue, reconstructing its locomotion and ecological role requires careful hydrodynamic modeling and comparison with both living and fossil marine organisms.
The phylogenetic position of Aquilamna within Lamniformes is also debated. While it clearly belongs to the order Lamniformes (which includes great white sharks, makos, and extinct megalodon), its precise relationships within this order are uncertain. The combination of primitive lamniform characters (e.g., long body, likely heterocercal tail) with highly derived fin morphology suggests it may represent a lineage that experimented with a completely different body plan from other lamniforms. Whether this represents an early branch in lamniform evolution or a later specialized side branch is unresolved.
What We Still Do Not Know About Aquilolamna
- Swimming mode: Unknown; no modern analogue.
- Diet: Hypothesized as filter-feeder or active predator; uncertain.
- Fin skeleton: Only soft tissue impression known; bony fin structure unknown.
- Phylogenetic position: Within Lamniformes debated.
In Depth
Aquilolamna is a genus of fish confirmed to have lived in the ocean around Mexico during the late Cretaceous. The name Aquilolamna means ‘eagle shark’, a reference to the long ‘wings’ formed by the pectoral fins and the general shark-like body. However, at the time of the naming of the genus, Aquilolamna was only tentatively placed with the sharks as key anatomical features to prove or disprove a link to sharks such as teeth were yet to be discovered and described.
In general Aquilolamna had a long round body, wide mouth and large pectoral fins. Pectoral fins are basically like hydrofoils and large fins are commonly seen in fast swimming fish. It is uncertain though if Aquilolamna was a fast swimmer, it could just as likely be that the enlarged pectoral fins allowed for energy efficient swimming, a real bonus if Aquilolamna was a planktonic filter feeder as is popularly thought. Many sharks, rays and other types of fish are known to be dedicated plankton feeders, and the evolution of Aquilolamna does seem to be convergent with these in terms of ecological niche. The late Cretaceous seas however were dangerous places with other larger sharks and mosasaurs possibly being predators of Aquilolamna.Further reading
- Manta-like planktivorous sharks in Late Cretaceous oceans. - Science. 371 (6535): 1253–1256. - Romain Vullo, Eberhard Frey, Christina Ifrim, Margarito A. Gonz�lez Gonz�lez, Eva S. Stinnesbeck & Wolfgang Stinnesbeck - 2021.
